Diabetes, a glucose metabolic disorder, is considered one of the biggest challenges associated with a complex complication of health crises in the modern lifestyle. Inhibition or reduction of the dipeptidyl peptidase IV (DPP-IV), alpha-glucosidase, and protein-tyrosine phosphatase 1B (PTP-1B) enzyme activities or expressions are notably considered as the promising therapeutic strategies for the management of type 2 diabetes (T2D). Various food protein-derived antidiabetic bioactive peptides have been isolated and verified. This review provides an overview of the DPP-IV, PTP-1B, and α-glucosidase inhibitors, and updates on the methods for the discovery of DPP-IV inhibitory peptides released from food-protein hydrolysate. The finding of novel bioactive peptides involves studies about the strategy of separation fractionation, the identification of peptide sequences, and the evaluation of peptide characteristics in vitro, in silico, in situ, and in vivo. The potential of bioactive peptides suggests useful applications in the prevention and management of diabetes. Furthermore, evidence of clinical studies is necessary for the validation of these peptides' efficiencies before commercial applications.

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The standard treatment for cancer is generally based on using cytotoxic drugs, radiotherapy, chemotherapy, and surgery. However, the use of traditional treatments has received attention in recent years. The aim of the present work was to provide an overview of medicinal plants effective on colon cancer with special emphasis on bioactive components and underlying mechanisms of action. Various literature databases, including Web of Science, PubMed, and Scopus, were used and English language articles were considered. Based on literature search, 172 experimental studies and 71 clinical cases on 190 plants were included. The results indicate that grape, soybean, green tea, garlic, olive, and pomegranate are the most effective plants against colon cancer. In these studies, fruits, seeds, leaves, and plant roots were used for in vitro and in vivo models. Various anticolon cancer mechanisms of these medicinal plants include induction of superoxide dismutase, reduction of DNA oxidation, induction of apoptosis by inducing a cell cycle arrest in S phase, reducing the expression of PI3K, P-Akt protein, and MMP as well; reduction of antiapoptotic Bcl-2 and Bcl-xL proteins, and decrease of proliferating cell nuclear antigen (PCNA), cyclin A, cyclin D1, cyclin B1 and cyclin E. Plant compounds also increase both the expression of the cell cycle inhibitors p53, p21, and p27, and the BAD, Bax, caspase 3, caspase 7, caspase 8, and caspase 9 proteins levels. In fact, purification of herbal compounds and demonstration of their efficacy in appropriate in vivo models, as well as clinical studies, may lead to alternative and effective ways of controlling and treating colon cancer.

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Diabetes mellitus is a chronic metabolic disease which is a serious global problem. In 2010 an estimated 285 million people had diabetes and within the next 20 years this value is expected to almost double. Many antidiabetic therapies focus on improving insulin sensitivity, increasing insulin production, and/or decreasing the level of blood glucose. Although a number of synthetic medicines are available, drugs of natural origin have aroused great interest. Triterpenes seem to demonstrate adequate properties. Many experiments have shown that these compounds have several antidiabetic mechanisms. They can inhibit enzymes involved in glucose metabolism, prevent the development of insulin resistance and normalize plasma glucose and insulin levels. These natural compounds, in contrast to synthetic drugs, apart from producing a hypoglycemic effect have also been found to manifest hypolipidemic and anti-obesity activity. Triterpenes are also promising agents in the prevention of diabetic complications. They have strong antioxidant activity and inhibit the formation of advanced glycation end products, implicated in the pathogenesis of diabetic nephropathy, embryopathy, neuropathy or impaired wound healing. Until now very few clinical studies have been concerned with the application of triterpenes in treating diabetes. However, due to their great therapeutic potential, these compounds deserve special attention.

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This article provides an overview of approximately 300 secondary metabolites with inhibitory activity against protein tyrosine phosphatase 1B (PTP1B), which were isolated from various natural sources or derived from synthetic process in the last decades. The structure-activity relationship and the selectivity of some compounds against other protein phosphatases were also discussed. Potential pharmaceutical applications of several PTP1B inhibitors were presented.

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The aim of the current study was to investigate the vasorelaxant activity of five structurally-related triterpenic acids namely ursolic (1), moronic (2), morolic (3), betulinic (4) and 3,4-seco-olean-18-ene-3,28-dioic (5) acids. The vasorelaxant effect of compounds 1-5 were determined on endothelium-denuded and endothelium-intact rat aortic rings pre-contracted with noradrenaline (0.1 μM). All compounds showed significant relaxant effect on endothelium-intact vessels in a concentration-dependent manner (p<0.05). Ursolic, moronic and betulinic acids were the most potent vasorelaxant agents with 11.7, 16.11 and 58.46 μM, respectively. Since vasorelaxation was blocked by L-NAME, while indomethacin did not inhibit the effect, endothelium-derived nitric oxide seems to be involved in triterpenic 2 and 3 mode of action. Compounds 1-5 were docked with a crystal structure of eNOS. Triterpenes 1-5 showed calculated affinity with eNOS in the C1 and C2 binding pockets, near the catalytic site; Ser248 and Asp480 are the residues that make hydrogen bonds with the triterpene compounds.

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